1. Field of the Invention
The present invention relates to an ink jet recording method, and an ink jet recording apparatus.
2. Description of the Related Art
In recent years, for ink jet inks, a pigment ink containing a pigment as a coloring material has been widely applied not only to a small printer for use in office and home applications but also to a wide format printer for use in applications where posters, advertisements, and CAD drawings are printed.
In recent years, various contrivances have been made on an apparatus and ink for use in an ink jet recording method, the improvement of the fastness property and image quality of a recorded article to be obtained has progressed, and the recording of an excellent image comparable to a silver salt photograph has been requested. In relation to the foregoing, in order that a high-definition image comparable to a silver salt photograph is obtained in the ink jet recording method, in particular, image graininess needs to be reduced. Since the ink jet recording method is such a system that an image is recorded with ink droplets ejected from nozzles, it can be said that the problem, i.e., graininess may inevitably arise in the image. In particular, upon printing with a wide format printer, a considerably large recording medium such as A0- or A1-size paper is often used. In such cases, the graininess of an image is apt to be remarkable, so the development of a method of effectively reducing the graininess of the image has been demanded.
A method of specifying a relationship between ink and a recording medium and a method of controlling changes in physical properties of ink have been heretofore proposed as methods of reducing the above image graininess. To be specific, a proposal concerning the use of a set of an ink and a recording medium having the following characteristic has been made (see Japanese Patent Application Laid-Open No. 2001-288388): a difference between the SP value of a water-soluble organic solvent or surfactant in the ink and the SP value of at least one kind of a material of which the surface coating layer of the recording medium is formed is set to 2 or less. In addition, a proposal concerning the use of an ink having the following characteristics has been made (see Japanese Patent Application Laid-Open No. 2004-292585): the ink is such that the change in viscosity and the change in surface tension are respectively 100% or less and 5% or less between the time when the ink is dried so that its weight is 80% of its initial weight and the time of the initial weight. Further, a proposal concerning the use of an ink set having the following characteristics has been made (see Japanese Patent Application Laid-Open No. 2006-117931): the ink set is formed of two or more kinds of inks having at least a dark ink and a pale ink independently, and the pigment of the dark ink and the pigment of the pale ink are different from each other in at least one of the crystalline form, particle diameter, chromophore, and dispersant.
In addition, an ink jet recording technique involves the problem that a phenomenon in which an image recorded with a pigment ink on a recording medium is blurred or stained occurs when water or the like contacts the image, that is, the water fastness of the image is insufficient. The following proposal has been made with a view to solving the problem, i.e., the insufficient water fastness of the image (see, for example, Japanese Patent Application Laid-Open No. H11-181341 and Japanese Patent Application Laid-Open No. H11-228898): the time period for which the image is dried after its recording is shortened by using an ink to which various surfactants or solvents are added. In addition, the following proposal has been made (see, for example, Japanese Patent Application Laid-Open No. 2000-351931 and Japanese Patent Application Laid-Open No. 2002-265831): an image is protected by forming a film on the surface of a recorded article with an ink containing various resin emulsions or polymer resins.